Replace "Add" button with "Create" in Create floor / area dialogs

[NoRi2909]

Proposed change

Currently most buttons and dialogs for floors and areas talk about "creating" them, starting with the action buttons:

But when you click those the final confirmation (for both items) there is an "Add" button:

To fix that PR does:

• Add a common "Create" string to avoid the 13th redefinition of that term.
• Replace "add" with "create" in both dialogs
• Replace "Removing" with "Deleting" in the corresponding dialog:

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes Inconsistent "Create" vs. "Add" plus "Delete" vs. "Remove" for Floors and Areas #23208
• This PR is related to issue or discussion:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io